If vertical interconnections could be fabricated at low cost, it would bring about many advantages, such as miniaturization and lower a height of the package. Our through-chip via (TCV) technology to fabricate vertical interconnections consists of a first via drilling by laser ablation (silicon drilling), followed by dielectric film lamination, a second via drilling by laser ablation (dielectric film drilling) and pattern plating of Cu. Our technology, being based on the printed-circuit-board fabrication process, has no need for expensive wafer fabrication techniques such as RIE, CVD and CMP. Thus, it enables the realization of the fabrication of through-chip vertical interconnections at low cost. In this paper, we describe the details of our process and its application in the fabrication of CMOS image sensor